The present invention relates to a poppet valve seal for an integrated pressure management system that manages pressure and detects leaks in a fuel system. The present invention also relates to a poppet valve seal for an integrated pressure management system that performs a leak diagnostic for the headspace in a fuel tank, a canister that collects volatile fuel vapors from the headspace, a purge valve, and all associated hoses.
In a conventional pressure management system for a vehicle, fuel vapor that escapes from a fuel tank is stored in a canister. If there is a leak in the fuel tank, canister or any other component of the vapor handling system, some fuel vapor could exit through the leak to escape into the atmosphere instead of being stored in the canister. Thus, it is desirable to detect leaks.
In such conventional pressure management systems, excess fuel vapor accumulates immediately after engine shutdown, thereby creating a positive pressure in the fuel vapor management system. Thus, it is desirable to vent, or xe2x80x9cblow-off,xe2x80x9d through the canister, this excess fuel vapor and to facilitate vacuum generation in the fuel vapor management system. Similarly, it is desirable to relieve positive pressure during tank refueling by allowing air to exit the tank at high flow rates. This is commonly referred to as onboard refueling vapor recovery (ORVR).
A sensor or switch signals that a predetermined pressure exists. In particular, the sensor/switch signals that a predetermined vacuum exists. As it is used herein, xe2x80x9cpressurexe2x80x9d is measured relative to the ambient atmospheric pressure. Thus, positive pressure refers to pressure greater than the ambient atmospheric pressure and negative pressure, or xe2x80x9cvacuum,xe2x80x9d refers to pressure less than the ambient atmospheric pressure.
The present invention is achieved by providing a seal for a poppet valve of an integrated pressure management apparatus. The poppet valve moves between an open position permitting fluid flow through an aperture in a housing and a closed position preventing fluid flow through the aperture. The seal comprises an annular body surrounding an axis and having first and second sealing surfaces, the first sealing surface being adapted to be fixed to the housing and surround the aperture, and the second sealing surface adapted to confront the poppet valve; and an annular lip projecting from the second sealing surface and adapted to be resiliently deformed by the poppet valve at the closed position, the annular lip projecting obliquely toward the axis in the open position.
The present invention is also achieved by a valve system for controlling fluid flow through an integrated pressure management apparatus. The valve system comprises a housing having an aperture; a poppet movable along an axis with respect to the housing, the poppet being movable between an open position permitting fluid flow through the aperture and a closed position preventing fluid flow through the aperture; and a seal surrounding the aperture at an interface between the housing and the poppet in the closed position, the seal having an annular lip projecting obliquely toward the axis and the poppet.
The present invention is further achieved by a method of sealing a movable poppet valve with respect to an aperture in a housing of an integrated pressure management system. The method comprises providing a seal positioned at an interface between the poppet valve and the housing, the seal having an annular lip projecting obliquely with respect to movement of the poppet valve; and deforming the annular lip upon occluding the aperture with the poppet valve, the deforming including scraping debris off the poppet valve.